An Agile Project Metrics developer tracks and analyzes key performance indicators in agile projects to ensure efficiency and productivity. They monitor metrics like velocity, burn-down and burn-up rates, cumulative flow, defect removal efficiency, and sprint burndown to gauge project performance. They also assess team velocity, work quality, and customer satisfaction. Their role involves collecting data, creating reports, and providing insights to aid decision-making. They help identify bottlenecks, manage risks, and facilitate continuous improvement. Their work is crucial in aligning project progress with business objectives, ensuring timely delivery, and promoting a culture of transparency and accountability.